Photopumped, pulsed, narrow line laser emission is demonstrated using cylindrical microcavities formed by &pgr;-conjugated polymer thin films wrapped around thin glass optical fibers and metal wires with various diametersD. A variety of cavity-dependent resonant laser mode structures were observed, which forD<10 &mgr;mcontain a single resonant spectral line of less than 1 Å in width. The microring lasers are also characterized by a well-defined, very low threshold excitation intensity, at which beam directionality and polarization degree dramatically increase. These findings open up the fields of lasers and fiber optics to organic materials. ©1998 American Institute of Physics.